1. Field of the Invention
The present invention relates to a cuvette for containing a liquid to be measured such as a specimen and a reagent for analyzing the constituents of plasma, urine, or others. Further, it relates to a cuvette-transporting apparatus for transporting the cuvette while controlling its position.
2. Description of Related Art
Conventional cuvettes and cuvette-transporting apparatuses are disclosed in Japanese Unexamined Utility Model Publication No. Hei 3(1991)-25157 and will hereinafter be explained with reference to FIGS. 6 and 7 which are a plan view and a vertical sectional view, respectively.
As shown in these drawings, a cuvette 1 is only of a cylindrical shape like a test tube and is provided with a flange 2 on the top thereof.
The cuvette-transporting apparatus comprises a chute 3 for transferring the cuvettes 1 with their heads (the top portion of the cuvette 1 which is open to receive the liquid) arranged in a line, and a positioning unit 4 for separating the cuvettes 1 from each other and for slightly lifting the cuvettes 1 up.
The positioning unit 4 is provided with a cylindrical space 5 having a rotator 8 rotatably inserted therein which comprises two circular boards 8 and 7 disposed parallel to each other.
Each of the circular boards 6 and 7 is provided with three arc-like notches 9, each notch being equally spaced on each circular board and located at upper and lower common positions. The notches 9 are formed so as to have the diameter thereof larger than the diameter of the body of the cuvette 1 and smaller than the diameter of the flange 2.
The positioning unit 4 has a motor 10 provided on the lower side, with a rotating shaft 11 of the motor 10 fixed into the rotator 8 at the center thereof, such that the motor 10 rotates the rotator 8 clockwise as shown in FIG. 8. Thus, the rotation of the motor 10 allows the cuvettes 1, together with the circular boards 6 and 7, to partially rotate around the center of the rotator 8.
In an outlet for the cuvettes 1 is provided a bottom guide 12 inclined such that the cuvettes 1 travel upward onto-the top of the guide. Further, lateral guides 13 and 14 are provided for slidingly contacting the lateral sides of the cuvettes 1 such that the lower circular board 6 is sandwiched therebetween.
Reference numeral 15 denotes a microswitch, for detecting the presence or absence of the cuvette 1, and numeral 16 denotes its actuator. The cuvettes 1, thus sequentially transferred in a line through the chute 3, are allowed to separate from each other and are individually inserted into the notches 9 of the circular boards 6 and 7 in a horizontal direction. In accordance with the rotation of the rotator 8, the cuvettes 1, together with the circular boards 6 and 7, are allowed to partially rotate around the center of the rotator 8.
After arriving at the foot of the bottom guide 12, the cuvette 1 travels upward with the outer bottom portion sliding on the bottom guide 12 to reach the top thereof and simultaneously is guided to the left by the lateral guides 13 and 14 (see FIG. 6). Thereafter, it is then detached from the notches 9 of the circular boards 6 and 7.
The cuvette 1, thus detached from the rotator 8, is resiliently held by a chucking finger with an arc-like inside to be transferred to a predetermined location.
The conventional cuvette 1 as described above has been, since it freely rotates, disadvantageous in measuring the properties of a liquid contained in the cuvette 1 by applying a measuring beam of light from a direction intersecting the vertical axis of the cuvette 1.
In order to precisely measure the absorption of transmitted light passing through the cuvette 1, a flat-surface is required to be formed on the cuvette 1 for applying the measuring beam of light. Such a flat surface, however, may not necessarily be irradiated with the measuring beam of light due to the rotation occurring during the transfer of the cuvette 1. Therefore the formation of the flat surface becomes useless.